On 2015-08-10 07:26:29 +0100, Simon Riggs wrote:
> On 10 August 2015 at 07:14, Peter Geoghegan <pg@heroku.com> wrote:
>
> > On Sun, Aug 9, 2015 at 11:03 PM, Simon Riggs <simon@2ndquadrant.com>
> > wrote:
> > > If 5) fails to bring a workable solution by the Jan 2016 CF then we
> > commit
> > > 2) instead.
> >
> > Is there actually a conflict there? I didn't think so.
> >
>
> I didn't explain myself fully, thank you for asking.
>
> Having a freeze map would be wholly unnecessary if we don't ever need to
> freeze whole tables again. Freezing would still be needed on individual
> blocks where an old row has been updated or deleted; a freeze map would not
> help there either.
>
> So there is no conflict, but options 2) and 3) are completely redundant if
> we go for 5). After investigation, I now think 5) is achievable in 9.6, but
> if I am wrong for whatever reason, we have 2) as a backstop.
I don't think that's true. You can't ever delete the clog without
freezing. There's no need for anti-wraparound scans anymore, but you
still need to freeze once.
Andres